How Much Vitamin B12 Should You Take?

Vitamin B-12 is an essential vitamin needed for optimal nerve and brain function. Some people need to take vitamin B-12 supplementation, especially vegetarians and those with certain medical conditions. Vitamin B-12 is naturally abundant in animal meats, which is why vegetarians may need supplementation. Other people may not absorb the vitamin well. Vitamin B-12 is available in capsule, tablet or liquid form. You may need more than the daily recommended intake, or DRI, established for you. Always talk to your doctor before taking this vitamin, and never take more than directed.

Factors

How much vitamin B-12 you should take may depend on how well your body absorbs the vitamin, not what type of vitamin B-12 supplement you take. According to a study published in the November 2006 edition of "Journal of Alternative and Complementary Medicine," there isn't a difference in the absorption or bioavailability of vitamin B-12 supplements, whether taking pill or sublingual forms. However, the delivery method and absorption differences come from intrinsic factors, such as medical condition. Further, the National Institutes of Health estimates that healthy people absorb about 10 mcg of a 500 mcg oral supplement.

DRI For Adults

People older than 14 should take 2.4 mcg of vitamin B-12 per day. According to the Food and Nutrition Board at the Institutes of Medicine, the DRI recommendations for vitamin B-12 are enough to meet the needs nearly 98 percent of healthy individuals.

DRI for Pregnant and Lactating Women

Pregnant and lactating women need more vitamin B-12 each day than the DRI established for other healthy adults. Pregnant women should take 2.6 mcg per day. Likewise, lactating women need 2.8 mcg per day. If you are pregnant or lactating and have vitamin B-12 malabsorption, your doctor may recommend a higher dose.

Adults Over 50

Adults over 50 should take more than 2.4 mcg recommended for those over the age of 14. The Linus Pauling Institute recommends those 50 and over 100 to 400 mcg per day because of the increased prevalence of malabsorption in this age group. This higher amount is available in B-complex supplements. The Institute also recommends eating fortified cereals because cereals provide vitamin B-12 in a form that is easily absorbed.

Considerations

There is little risk of vitamin B toxicity, so there is not a tolerable upper intake level, also called UL, for vitamin B-12. Your medical or naturopathic doctor might recommend more than the DRI established for vitamin B-12. Even though there is little risk of toxicity, do not double up on the dose recommended for you. According to Drugs.com, if you skip your daily dose, take your missed dose as soon as you can. However, if it is too close to your next daily dose, wait and you're your next daily dose without double dosing.